Converging evidence indicates that an individual's difficulty tolerating distress has important links to substance abuse, a key behavior that places adolescents at risk for HIV (Brandon et al., 2003;Brown, Lejuez, Kahler, &Strong, 2002;Daughters, Lejuez, Bornovalova et al., 2005;Daughters, Lejuez, Kahler et al., 2005;Quinn, Brandon, &Copeland, 1996). This body of research has emerged from studies with adult drug abusers utilizing behavioral measures of distress tolerance to assess one's ability to persist in goal directed behavior in the presence of intense emotional discomfort, or simply, one's ability to effectively tolerate emotional distress. More recently, we have established a similar link in adolescents (Daughters, Lejuez et al., 2007). Although links of low distress tolerance with risky sexual behavior have not been examined previously, there are theoretical and empirical reasons that suggest that this link may exist as well (see Lejuez, 2007). Given compelling evidence that an individual's difficulty tolerating distress has important links to substance abuse, and potential links to risky sexual behavior, attempts to understand the precursors of distress tolerance in adolescents have considerable public health relevance. Several theoretical perspectives and considerable empirical evidence suggest that the emotional climate of the family and the quality of family relationships have major implications for a child's functioning, including engagement in risk behaviors (e.g., Bornstein, 2002;Maccoby, 2007). Further, examination of theory and research (e.g., Bowlby, 1969/1982;Cassidy &Shaver, 1999;Eisenberg et al., 1998;Gottman et al., 1996, 1997) suggests two aspects of family emotional climate that may be linked to adolescent distress tolerance: (a) maternal response to distress, and (b) adolescent attachment. Thus, it appears useful to examine links between family factors and adolescent capacity to tolerate emotional distress, and the subsequent development of HIV risk behavior. The proposed cross-sectional study has several goals. First, we seek to extend previous work examining links between adolescent distress tolerance and HIV risk behavior by providing further evidence of the link between adolescent distress tolerance and substance use, as well as by examining, for the first time, the link between distress tolerance and risky sexual behavior. Second, we will attempt to elucidate risk factors for low distress tolerance by focusing on the family emotional climate. Finally, in the context of a negative- reinforcement-based model of HIV risk, we will examine distress tolerance as a mediator of the link between family emotional context and HIV risk behavior. An advantage of this study is that participants (240 13- to 16- year-olds) will be taken from an ongoing longitudinal study of HIV risk behavior that does not address family emotional climate. This approach is cost effective and provides opportunities to enhance an existing data set including other relevant indicators of HIV from genetic vulnerability and environmental adversity through behavioral measurement of risk-taking propensity. PUBLIC HEALTH RELEVANCE Considerable evidence indicates that difficulties persisting in goal-directed behavior in the context of emotional distress (distress intolerance) is linked to substance use problems. We will expand the scope of this work in two important and innovative ways: (a) by examining whether distress intolerance is also linked to risky sexual behavior, and (b) by considering whether distress intolerance can be predicted by family emotional context. Because these data will contribute to the development of a more comprehensive model of vulnerability to HIV risk behavior, they will in turn be useful in creating effective intervention programs.